Neem is thought to come from northeast India and Myanmar. It has been used to treat infections, skin conditions, and swellings. Neem is also used as a pesticide to protect food and other products from insects. Neem leaves and seed oil are believed to benefit the skin and hair.

Neem extracts often have a strong, overpowering smell similar to that of garlic.

Neem may help reduce plaque in the mouth, repel mosquitoes, treat psoriasis (a skin condition that causes redness and irritation), and help heal ulcers in the stomach and intestines. However, there is a lack of evidence to support these uses at this time.

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

GRADE *

Early research suggests that neem may help slow the progression of HIV/AIDS. Further high-quality studies are needed in this area.

C

Early studies have found that neem may have protective effects against flies. More research is needed to make a firm conclusion.

C

Neem seed extract in shampoo has been found to be effective for treating head lice. Further high-quality studies are needed.

C

Neem oil and neem cream may protect against mosquito bites. Further research is needed before a firm conclusion can be made on the use of neem as a mosquito repellent.

C

Neem may help reduce germs and plaque in the mouth. The effects of neem have been compared to those of chlorhexidine, a prescription drug used to treat gum disease. Further study is needed in this area to make a firm conclusion.

C

Neem has been studied for psoriasis, with limited information available. There is a lack of evidence at this time to support the use of neem for this condition.

C

Neem has been found to have protective, healing effects on ulcers of the stomach and intestines. However, research is still needed to compare the effects of neem to those of standard treatments.

C

* Key to grades

A: Strong scientific evidence for this useB: Good scientific evidence for this useC: Unclear scientific evidence for this useD: Fair scientific evidence for this use (it may not work)F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

For ulcers of the stomach and intestines, neem bark extract has been taken by mouth in doses of 30-60 milligrams twice daily for 10 weeks.

For dental plaque, a gel containing neem extract has been applied to the teeth and gums twice a day, before bed and after breakfast, for six weeks. A neem extract mouthwash has been rinsed in the mouth for one minute, twice daily for two weeks, 30 minutes after brushing the teeth. Toothbrushes have been soaked for 12 hours in a 3 percent neem solution before brushing the teeth.

As an insect repellent, 3 milliliters of diluted neem root or leaf extracts has been applied to the skin for two days.

As a mosquito repellent, neem cream (5 percent neem oil in vanishing cream base) has been applied to the skin. Doses of 3-5 milliliters of 0.5-2 percent neem oil have been applied to the skin for up to 12 nights.

For psoriasis, neem capsules have been taken by mouth three times daily after applying crude coal tar and salicylic acid, taking a bath, and having 15 minutes of sun exposure, for 12 weeks.

Children (younger than 18 years)

General: There is no proven safe or effective dose for neem in children. Toxic brain disorders have been reported with the use of neem.

For dental plaque, a neem extract mouthwash, with and without an alcohol base, has been rinsed in the mouth daily after lunch for two months.

Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Avoid in people with known allergy or sensitivity to neem (Azadirachta indica) or members of the Meliaceae family. Allergic skin reactions (including burning and itching) have been reported.

Side Effects and Warnings

The following forms and doses of neem are likely safe: neem bark extract, when taken by mouth in doses of 30-60 milligrams for up to 10 weeks; neem leaf extract gel or mouthwash, when used in the mouth for up to six weeks; and 5 percent neem cream or 0.5-2 percent neem oil, when applied to the skin to repel insects for up to two weeks.

Neem may lower blood sugar levels. Caution is advised in people with diabetes or low blood sugar, and in those taking drugs, herbs, or supplements that affect blood sugar. Blood sugar levels may need to be monitored by a qualified healthcare professional, including a pharmacist, and medication adjustments may be necessary.

Neem may cause low blood pressure. Caution is advised in people taking drugs or herbs and supplements that lower blood pressure.

Neem may interfere with the way the body processes certain drugs using the liver's "cytochrome P450" enzyme system.

Use cautiously in people who have heart conditions, liver disease, and thyroid conditions.

Avoid in people with known allergy or sensitivity to neem (Azadirachta indica) or members of the Meliaceae family.

Avoid taking neem by mouth, due to the risk of toxic brain disorders. Avoid using in infants, children, pregnant women, and people who are trying to conceive.

Pregnancy and Breastfeeding

There is a lack of scientific evidence on the use of neem during pregnancy or breastfeeding. Avoid in pregnant women and those who are trying to conceive, as neem may cause abortion.

Neem may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. People taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.

Neem may interfere with the way the body processes certain drugs using the liver's "cytochrome P450" enzyme system. As a result, the levels of these drugs may be altered in the blood, and may cause altered effects or potentially serious adverse reactions. People using any medications should check the package insert, and speak with a qualified healthcare professional, including a pharmacist, about possible interactions.

Neem may also interact with acetaminophen, agents for the blood, agents for the heart, agents for the lungs, agents for the nervous system, agents for the skin, agents for the stomach and intestines, agents that are toxic to the liver, agents that cause abortion, antibiotics, anticancer agents, antiprotozoal agents, antiseptic agents, anti-ulcer agents, antiviral agents, birth control, cyclophosphamide and mitomycin C, fertility agents, heart rate-regulating agents, hormonal agents, insect repellants, morphine, quinine, and thyroid hormones.

Interactions with Herbs and Dietary Supplements

Neem may interfere with the way the body processes certain herbs or supplements using the liver's "cytochrome P450" enzyme system. As a result, the levels of other herbs or supplements may be altered in the blood. It may also alter the effects that other herbs or supplements possibly have on the P450 system.

Neem may lower blood sugar levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

Neem may cause low blood pressure. Caution is advised in people taking herbs or supplements that lower blood pressure.

Neem may also interact with antibacterials, anticancer herbs and supplements, anti-parasite herbs and supplements, antiseptic herbs and supplements, anti-ulcer herbs and supplements, antiviral herbs and supplements, birth control, fertility herbs and supplements, garlic, heart rate-regulating herbs and supplements, herbs and supplements for the blood, herbs and supplements for the heart, herbs and supplements for the lungs, herbs and supplements for the nervous system, herbs and supplements for the skin, herbs and supplements for the stomach and intestines, herbs and supplements that are toxic to the liver, herbs and supplements that cause abortion, hormonal herbs and supplements, insect repellants, thyroid hormones, and uterine stimulants.

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.